Additive manufacturing of complex volumetric structures opened new frontiers in many technological fields, turning previously inconceivable designs into a practical reality. Electromagnetic components, including antenna and waveguiding elements, can benefit from exploring the third dimension. While fused deposition modeling (FDM) polymer printers become widely accessible, they manufacture structures with moderately low electromagnetic permittivities, compared to metals. However, metal 3D printers, being capable of producing complex volumetric constructions, remain extremely expensive and hard to maintain apparatus, suitable for high-end market applications. Here we develop a new metal printing technique, based on a low-cost and simple FDM device and subsequent electrochemical deposition. For testing the new method, we fabricated several antenna devices and compared their performances to standard printed FeCl3 etched board-based counterparts, demonstrating clear advantages of the new technique. Our new metal printing can be applied to manufacture electromagnetic devices as well as metallic structures for other applications.

Parametric retrieval of electromagnetic properties is important for both new materials characterization and an accurate design of devices. While quite a few techniques have been developed over the years, precise mapping of high-permittivity samples remain challenging. Here we advance a so-called micro-strip technique, where transmission coefficients of a waveguide system with an analyte on top are used to extract electromagnetic parameters of the later. Our cross-like strip line configuration has a split ring resonator on one edge and an open circuit termination on another. This design allows performing a simultaneous test of cylindrical and rectangular samples. Our new post-processing scheme was tested on a water-filled container and showed 96.3% accuracy, assessed by comparing our results with tabulated data.